WO2019011916A1 - Dispositif et procédé de correction de perturbations pour procédés de mesure d'écoulement optiques - Google Patents

Dispositif et procédé de correction de perturbations pour procédés de mesure d'écoulement optiques Download PDF

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Publication number
WO2019011916A1
WO2019011916A1 PCT/EP2018/068669 EP2018068669W WO2019011916A1 WO 2019011916 A1 WO2019011916 A1 WO 2019011916A1 EP 2018068669 W EP2018068669 W EP 2018068669W WO 2019011916 A1 WO2019011916 A1 WO 2019011916A1
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WIPO (PCT)
Prior art keywords
light
wavelength
flowing fluid
wavefront
camera
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PCT/EP2018/068669
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German (de)
English (en)
Inventor
Lars Büttner
Jürgen Czarske
Martin TEICH
Nektarios KOUKOURAKIS
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Technische Universität Dresden
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Application filed by Technische Universität Dresden filed Critical Technische Universität Dresden
Priority to EP18743430.3A priority Critical patent/EP3652578B1/fr
Priority to CN201880046397.4A priority patent/CN110914736B/zh
Priority to US16/628,391 priority patent/US10921585B2/en
Publication of WO2019011916A1 publication Critical patent/WO2019011916A1/fr

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Classifications

    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B26/00—Optical devices or arrangements for the control of light using movable or deformable optical elements
    • G02B26/06—Optical devices or arrangements for the control of light using movable or deformable optical elements for controlling the phase of light
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
    • G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
    • G01F1/66—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by measuring frequency, phase shift or propagation time of electromagnetic or other waves, e.g. using ultrasonic flowmeters
    • G01F1/661—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by measuring frequency, phase shift or propagation time of electromagnetic or other waves, e.g. using ultrasonic flowmeters using light
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/0025—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00 for optical correction, e.g. distorsion, aberration
    • G02B27/0068—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00 for optical correction, e.g. distorsion, aberration having means for controlling the degree of correction, e.g. using phase modulators, movable elements

Definitions

  • the invention relates to an arrangement and a method for disturbance correction for flow measuring methods, in particular imaging flow measuring methods.
  • static objects eg. B.
  • optical access windows under certain conditions, eg. B., if they have a curvature, cause optical interference.
  • Fluctuating disturbances can not be compensated by means of rigid correction optics.
  • One approach, in particular for film flows, is the use of a stationary background image, which is z. B. is located on the wall of a flow channel and at the same time for flow measurement through the free surface is observed through. Based on the distortion of the background image, the z. B. represents a dot pattern, conclusions about the distortion of the measurement image can be drawn and a software-side computational correction of the measurement image can be performed.
  • An example of such a software-side correction method is the Background Schlieren Method (BOS for Background Oriented Schlieren). The Z. In Richard, H. and Raffel, M .: Principle and Applications of the Background Oriented Schlieren (BOS) method.
  • Measurement Science and Technology, 12 (2001), pp. 1576-1585 has been developed essentially for the visualization of density or refractive index gradients in transparent media. It measures the apparent background point movement caused by refractive index gradients by first taking a picture of the background without the refractive index gradient between the background and the camera. This image is used as a reference image. The second required image - the measurement image - is taken with the refractive index gradient to be examined between the background and the camera. The background points are compared to the reference image on a different part of the image. The shift of the background points between the two images can be accurately determined by the cross-correlation if the background has an irregular dot pattern with marked contrast.
  • the result of the cross-correlation represents a displacement vector field between points on the reference image and points on the measurement image from which the refractive index gradient field can be calculated and which can ultimately be used for software correction of the flow measurement data.
  • the BOS method does not offer a possibility for the correction of optical interference on the hardware side.
  • US Pat. No. 7,118,216 B2 discloses a scanning laser ophthalmoscope for examining the ocular fundus, in which light reflected from the retina is proportionally directed to a wavefront sensor in order to detect the wavefront distortion caused by the eye, one in the optical path arranged deformable mirror is controlled so that the wavefront distortion is compensated for imaging. Special demands on the speed of the control system are not made in this field of application.
  • the method described requires that each pixel of the camera produce a virtual image on a corresponding pixel of the area light modulator, and vice versa, thereby requiring a complex calibration and a very high degree of accuracy high adjustment effort, instantaneous corrections, especially fluctuating disturbances, can not be made.
  • US 2015/01601 18 A1 shows an optical measuring system for measuring liquid samples which are mounted in the holes of microplates.
  • the system has u.a. a light source for illuminating the samples and a detector for measuring the optical signals. Between the light source and the holes, an optical element such as a spatial light modulator is arranged, which corrects distortions at the interface of the liquid samples.
  • US 2010/0195048 A1 discloses the use of adaptive optics in the medical field, especially for ophthalmoscopy, by which inter alia the retina of the eye is examined.
  • a part of the eye is scanned by a first optical module, wherein the reflected light is conducted into a detection device and images the examined part of the eye.
  • a second optical module detects and corrects the optical distortion.
  • the scattering of the light on the tissue leads to multiple reflections, which means that no defined interfaces can form.
  • the disadvantage is the correction of the optical Distortion on the retina so only in sections, namely line by line and thus done in a small scale area, since the first module has a line scanner for scanning the eye. An instantaneous correction of the complete field of view is thus not possible.
  • the measuring method is based on a confocal designed principle, the scattered light of the surrounding tissue layers is deliberately suppressed by Pinholes in the beam path of the device, so that it does not arrive in the detector and the optical imaging quality of the approached by the scanner measurement region is improved.
  • the object of the present invention is therefore to overcome the disadvantages of the prior art and to provide an arrangement and a method by means of which optical disturbances caused by a continuous phase transition interface between two fluids with different optical density can be corrected instantaneously and on the hardware side ,
  • the arrangement and the method are intended to enable a large-scale correction of the optical disturbances on optically flat and extensively formed interfaces using the Fresnel eflex.
  • the object is achieved by a wavefront sensorless arrangement for correcting optical interference by an interface with the features of claim 1 and a wavefront sensor-based arrangement for correcting optical interference by an interface with the features of claim 9 and a wavefront sensorless method for correcting optical interference through an interface with the features of claim 8 and a wavefront sensor based.es method for correcting optical interference by an interface with the features of claim 16. Further developments of the invention are specified in subclaims.
  • the solution according to the invention is based thereon in imaging flow measurement methods which are used for measuring, for.
  • a flowing fluid can be used to correct optical interference caused by an interface by means of a wavefront modulator.
  • the solution according to the invention can be implemented wave front sensorless or wavefront sensor based.
  • the solution according to the invention offers the possibility for hardware-side, instantaneous correction of optical interference. It is particularly advantageous that the invention can be operated in real time by using fast components and algorithms.
  • real-time it is to be understood that the frequency of the reaction to the fluctuation or temporal change of the optical disturbance, ie the targeted change in the setting of the wavefront modulator, is higher than the fluctuation frequency of the optical disturbance.
  • interface as an area in which fluids with different optical density or different refractive indices meet, in the sense of the invention comprises optically large-scale, even and continuously formed phase transition interfaces, light is reflected at these interfaces according to Fresnel's formulas Term "interface” in addition to interfaces such.
  • the invention is especially for fluctuating interfaces, but also for static interfaces, eg. B. optical access windows, suitable.
  • fluid is understood to mean a liquid, a gas or a vapor, ie a non-solid continuum to which the laws of fluid mechanics are applicable.
  • a “wavefront modulator” is a device for selectively influencing the phase and / or the amplitude of a light wave
  • the wavefront modulator can have individually controllable elements as actuators and thus a pixel structure or a continuously variable actuator layer or have a reflective illuminated surface.
  • the invention can be applied to all imaging flow methods in which an image field of the flow is viewed contactlessly with a camera.
  • Examples include Particle Imaging Velocimetry (PIV), Particle Tracking Velocimetry (PTV), Molecular Tagging Velocimetry (MTV) or Doppler Global Velocimetry.
  • PIV Particle Imaging Velocimetry
  • PTV Particle Tracking Velocimetry
  • MTV Molecular Tagging Velocimetry
  • Doppler Global Velocimetry Doppler Global Velocimetry.
  • the invention is used in the PIV process.
  • the flowing fluid must contain particles that interact with the illumination used in the imaging flow measurement method.
  • particles called “tracers” are usually introduced as measuring objects in the flowing fluid, which visualize the flow without significantly affecting it, the tracer comprising scattering particles or fluorescently formed particles, hereinafter referred to as fluorescent particles
  • the scattering particles have no fluorescent properties and, in embodiments, the scattering particles are embodied as silver-coated hollow glass spheres with a diameter of approximately 10 ⁇ m
  • the fluorescent particles have fluorescent properties and emit light according to Stokes's rule.
  • the terms "scattering” or “scattered light” are used, whereby in the case of scattering particles they refer to the diffuse reflection and in the case of fluorescent particles to the emitted light.
  • the flowing fluid has intrinsic scattering particles or intrinsically fluorescent particles, by means of which the flow can be visualized, the addition of tracers is not necessary.
  • the intrinsically formed scattering particles or fluorescent particles are summarized below under the term “intrinsic particles.” Unless otherwise stated, the term “tracer” is always used below, wherein in the presence of intrinsic particles in the fluid instead of the tracer, the intrinsic particles are meant ,
  • the wavefront sensorless device for the correction of interfacial optical disturbances in imaging flow measurement methods used to measure a flowing fluid, wherein the flowing fluid contains tracers formed as scattering particles, comprises an illumination source configured to illuminate a measurement field
  • a stationary, characteristic optical pattern, frequently also referred to as "background pattern" is arranged in the measuring field illuminated by the illumination source, for example a laser is used as the illumination source
  • the measuring field can be, for example, that of the illumination source be illuminated region of a flow channel, which is traversed by the flowing fluid.
  • the wavefront sensorless arrangement according to the invention has a camera which is designed for, in particular simultaneous, recording of the flow pattern and of the pattern image.
  • the image of the light scattered by the tracers in the flowing fluid is referred to as the "flow image” and the image of the light scattered by the stationary background pattern is referred to as a "pattern image”.
  • the flow pattern corresponds to a direct representation of what happens to the measured objects in the flow.
  • the term "camera” encompasses all optical apparatuses with which an image can be recorded on a storage medium and / or transmitted via an interface for further processing, eg also detector arrays.
  • the illumination source and / or the camera are arranged in such a way that the illumination and / or the observation of the flowing fluid and the background pattern takes place through an interface.
  • both the illumination source and the camera are arranged so that the illumination and the observation of the flowing fluid takes place through an interface.
  • the wavefront sensorless arrangement according to the invention has a controllable wavefront modulator which is arranged in the optical path between the measuring field and the camera or in the optical path between the illumination source and the measuring field or in the optical path between the illumination source and the measuring field and between the measuring field and the camera is.
  • the controllable wavefront modulator is preferably arranged in the optical path between the measuring field and the camera.
  • the wavefront sensorless arrangement has a signal processing platform which is designed to evaluate at least the pattern image, wherein the pattern image is compared with the background pattern to determine a quality factor of the image, and the wavefront modulator is driven to align it.
  • the signal processing platform is connected in terms of information technology with the camera and with the wavefront modulator, wherein the information technology connection can be wire-based or wireless.
  • the driving of the wavefront modulator takes place by the signal processing platform in such a way that the quality factor is iteratively optimized.
  • O. B. d. A. is the figure of merit as a measure of the optical similarity of the pattern image, ie the image of the background pattern, with the actual background pattern, defined in such a way that it increases with increasing optical similarity between the pattern image and the background pattern.
  • the wavefront modulator is controlled and aligned by the signal processing platform in such a way that the quality factor of the background pattern on the camera after the interaction of the light scattered by the background pattern with the wavefront modulator is increased.
  • Suitable quality factors are z.
  • sharpness metrics such as the maximum spatial frequency, the maximum standard deviation, the brightness histogram, the intensity gradient or the cross-correlation coefficient.
  • the normalized cross-correlation coefficient is ⁇ 1, where a normalized cross-correlation coefficient of 1 corresponds to the complete match of the pattern image and the background pattern.
  • the quality factor can also be defined in another suitable form, for. B. such that it decreases with increasing optical similarity, ie decreasing deviation, between the pattern image and the background pattern, and it is understood that the control of the wavefront modulator then takes place in such a way that reduces the quality factor.
  • the driving of the wavefront modulator takes place in such a way that the optical similarity between the pattern image and the background pattern increases.
  • the setting of the Wavefront modulator adapted so that the surface caused by the optical interference corrects, preferably compensated as much as possible is.
  • the image of the tracer ie the flow image
  • the evaluation of the flow image is preferably carried out via the same signal processing platform as the evaluation of the pattern image, but can also take place via a suitable other signal processing platform.
  • the wavefront sensorless arrangement according to the invention can also have further, suitably arranged optical components, in particular beam splitters, reflection prisms and filter elements.
  • the optimization of the quality factor takes place in an iterative way.
  • the optimization is completed when the quality factor reaches an optimum.
  • the optimization algorithm Since, in the case of a fluctuating or time-varying disturbance, the quality factor deviates from the optimum value over time, the optimization algorithm is repeated continuously. It is thus possible to react instantaneously to changes in the optical disturbance through the interface.
  • the wavefront sensorless arrangement is characterized by a particularly simple structure and is therefore inexpensive to implement among other things.
  • the wavefront sensorless arrangement requires no additional optical access to the measuring point.
  • the flowing fluid contains fluorescent particles, the pattern being non-fluorescent, or the pattern is fluorescent, wherein the flowing fluid contains no fluorescent particles, or the flowing fluid contains fluorescent particles, and the pattern is fluorescent wherein the fluorescence wavelength of the fluorescent particles and that of the pattern are different from each other.
  • the flowing fluid contains tracers or intrinsic particles, these can either be introduced as fluorescent particles into the fluid, or the fluid has intrinsically fluorescent particles by means of which the flow can be visualized, so that the addition of tracers is not necessary.
  • the pattern is fluorescent, it is to be understood that the material, for. For example, the paint that makes up the pattern has at least one fluorescent constituent.
  • Fluorescent means that the particles or at least one component of the pattern are optically brought into an excited state by illumination and relax within a short time (order of magnitude approximately ms and smaller) after the excitation with emission of light.
  • the wavelength of the scattered light is usually greater than the wavelength of the illumination (stokes rule).
  • wavelength as used herein always includes a certain, narrow wavelength range of several tens of nm around the wavelength, for example the natural linewidth of a spectral line, or the line broadening mechanisms (eg, the Doppler effect due to thermal Movement) underlying line width of the fluorescent light.
  • the wavefront sensorless arrangement according to the invention has a first and a second camera.
  • Means for wavelength selection are arranged in the optical path between the measuring field and the two cameras.
  • the means for wavelength selection are designed so that light of a first wavelength with a first camera and light of a second wavelength with a second camera is detected.
  • the described embodiment advantageously makes it possible to separate the flow pattern and the pattern image since the wavelength of the light scattered on the tracers of the flowing fluid and the wavelength of the light scattered on the pattern are different from each other.
  • the wavelength of the light scattered by the fluorescent particles is i. d. R. is greater than the wavelength of the pattern-scattered light corresponding to the wavelength of the illumination.
  • about the means for wavelength selection is o. B. d. A. the flow image then imaged on the first camera, and the pattern image on the second.
  • the pattern is formed fluorescent and the particles are non-fluorescent, or if the flowing fluid contains fluorescent particles and the pattern image is formed fluorescent, the fluorescence wavelengths are different from each other.
  • the wavelength selection means may be formed as a partial reflection means comprising a reflection acting as a wavelength-dependent beam splitter, wherein a first wavelength light is predominantly deflected towards the one camera and a second wavelength light is distracted to a large extent in the direction of the second camera.
  • the means for partial reflection are thus z. B. formed in such a way that light of the first wavelength is reflected to a predominant proportion in the direction of a camera and light of the second wavelength to a predominant proportion in the direction of the second camera is transmitted, or z. B. such that light of the first wavelength transmits to a predominant proportion in the direction of the first camera and light of the second wavelength is reflected to a predominant proportion in the direction of the second camera.
  • a large part of the scattered light is used for imaging.
  • the means for wavelength selection may comprise a wavelength-independent beam splitter and wavelength-selective filter elements.
  • the wavelength-independent beam splitter By means of the wavelength-independent beam splitter, the distribution of the light scattered on the tracers or on the pattern takes place independently of its wavelength into a first and a second portion with mutually different directions of propagation, the first and second portions scattering both on the tracers and on the pattern May contain light.
  • the filter elements are arranged in the optical path of the first portion, by means of which light of the first wavelength can pass the filter elements in the direction of the first camera or is deflected in the direction of the first camera, wherein light of the second wavelength, the filter elements not can happen or is deflected so that no image on the first camera takes place. For example, only the flow pattern is displayed on the first camera.
  • Filter elements are arranged between the beam splitter and the second camera in the optical path of the second portion, by means of which light of the second wavelength can pass the filter elements in the direction of the second camera or is deflected in the direction of the second camera, wherein light of the first wavelength is not the filter elements can happen or is deflected so that no image on the second camera takes place. Remaining in the above example, only the pattern image will be displayed on the second camera.
  • This embodiment is characterized by a particularly simple and inexpensive construction.
  • the wavefront modulator of the wavefront sensorless device comprises a combination of a plurality of adaptive optical correction elements.
  • image tilting by electrically operated galvanometer mirrors and defocus aberrations can be corrected by adaptive lenses.
  • Remaining optical disturbances can be corrected for example by a surface light modulator.
  • the individual adaptive optical correction elements are operated in series and in each case by a control circuit assigned to the respective correction element.
  • the wavefront modulator of the inventive wavefront sensorless device is based on a surface light modulator having a reflective illuminated surface.
  • the reflective area light modulator comprises a deformable mirror having a continuously illuminated surface or an array of micromirrors that are individually alignable.
  • the signal processing platform has an FPGA (Field Programmable Gate Array) or a graphics processor or a digital signal processor or a combination thereof.
  • FPGA Field Programmable Gate Array
  • the control rate of the drive of the wavefront modulator must be at least twice as high as the maximum fluctuation frequency of the optical disturbance occurring.
  • the inventive method for wavefront sensorless correction of optical interference by an interface in imaging flow measurement method for measuring a flowing fluid wherein the flowing fluid contains tracer, which are formed as scattering particles, and wherein in the illuminated by an illumination source measuring field, which is flowed through by the flowing fluid , a fixed optical pattern is arranged, is characterized in that the flowing fluid is illuminated with an illumination source, the driving of a wavefront modulator, in the optical path between the measuring field and a camera or in the optical path between the illumination source and the measuring field or in the optical path is arranged between the illumination source and the measuring field and between the measuring field and the camera, wherein the camera at least for recording the flow image as a disordered image of scattered by the tracers in the flowing fluid light and the pattern image serves as a disordered image of the light scattered by the stationary pattern, is arranged by a signal processing platform such that a quality factor determined by comparing the pattern image with the pattern is iteratively optimized.
  • the flow image is corrected and these disturbances in the flow pattern preferably largely compensated.
  • Such a wavefront sensorless method according to the invention can have, for example, the following method steps: a. Illumination of the measuring field, which is traversed by the tracer having flowing fluid and in which a stationary background pattern is arranged;
  • the flowing fluid contains tracers which are formed as fluorescent particles. That is, either fluorescent particles are introduced into the fluid for its measurement, or the fluid has intrinsically fluorescent particles, by means of which the flow can be visualized, so that the addition of tracers is not necessary.
  • the inventive wavefront sensor-based arrangement has at least one illumination source, for. As a laser on, by means of which a measuring field and thus the flowing Fluid is illuminated by an optical interference-causing interface with light at least one illumination wavelength.
  • the wavefront sensor-based arrangement according to the invention has a wavefront sensor, which is designed to detect the light reflected from the interface according to the Fresnel formulas, this light having the at least one illumination wavelength.
  • the interfaces must be optically flat, continuous and large-scale.
  • a "wavefront sensor” is an arrangement by means of which a wavefront test for determining the shape of the surfaces of the same phase of a shaft can be carried out.Formations of the wavefront can be determined instantaneously by means of the wavefront sensor.
  • the inventive wavefront sensor-based device also has a camera by means of which the flow image is recorded, wherein the flow image represents the noisy image of the light scattered by the tracers of the flowing fluid, this light having a different wavelength from the at least one illumination wavelength. Therefore, in the case of a wavefront sensor-based arrangement, the tracers are preferably designed as fluorescent particles.
  • means for partial reflection are arranged in the optical path between the measuring field and the wavefront sensor and between the measuring field and the camera, said means having a also referred to as "dichroic mirroring, their degree of reflection and transmittance is a function of the wavelength of the light and thereby acts as a wavelength-dependent beam splitter, which means that the light of the at least one illumination wavelength, in particular the light reflected from the interface, is deflected to a predominant extent in the direction of the wavefront sensor, and Light of a wavelength which is different from the at least one illumination wavelength, in particular the light scattered by the fluorescent particles, is deflected to a predominant extent in the direction of the camera reflect such that light of the at least one illumination wavelength is predominantly reflected in the direction of the wavefront sensor, and light of a wavelength different from the at least one illumination wavelength is transmitted to a predominant proportion in the direction of the camera.
  • these means act in such a way that light of the at least one illumination wavelength transmits to a predominant proportion in the direction of the wavefront sensor and light of one of the at least one illuminates Illumination wavelength of different wavelengths is reflected to a large extent in the direction of the camera.
  • the flowing fluid contains scattering particles, wherein the measuring field traversed by the flowing fluid is illuminated by light of a first illumination source with an illumination wavelength through the interface and the scattering particles are illuminated with light from a second illumination source at a wavelength different from the illumination wavelength ,
  • the camera for recording the flow pattern is formed as an image of the scattered by the scattering particles of the flowing fluid light of the wavelength different from the illumination wavelength.
  • the means for partial reflection arranged between the measuring field and the camera are designed as beam splitters.
  • the wavefront sensor-based arrangement according to the invention furthermore has a controllable wavefront modulator which is located in the optical path between the measuring field and the camera and between the measuring field and the wavefront sensor or in the optical path between the at least one illumination source and the measuring field or in the optical path between the at least one illumination source and between the measuring field and the camera and between the measuring field and the wavefront sensor.
  • the controllable wavefront modulator is preferably arranged in the optical path between the measuring field and the camera and between the measuring field and the wavefront sensor.
  • the wavefront sensor-based arrangement has at least one signal processing platform which is designed to at least evaluate the data detected by the wavefront sensor with the aim of determining the wavefront distortion due to the optical interference by the interface and to control the wavefront modulator.
  • the signal processing platform is connected in terms of information technology, at least with the wavefront sensor and with the wavefront modulator, wherein the information technology connection can be wire-based or wireless.
  • the driving of the wavefront modulator takes place by means of the signal processing platform such that by interaction with the wavefront modulator, essentially transmission and / or reflection, the wavefront distortion caused by scattering of the interface is corrected, preferably largely compensated.
  • the wavefront modulator can be aligned such that the inverse of the wave front distortion measured by the wavefront sensor is impressed on the light when interacting with the wavefront modulator.
  • the signal processing platform is also used to evaluate the flow pattern; the evaluation However, the flow pattern can also be performed on a second signal processing platform.
  • the wavefront sensor-based arrangement according to the invention can also have further, suitably arranged optical components, in particular further beam splitters, reflection prisms and / or filter elements.
  • the inventive wavefront sensor-based arrangement operates as a closed loop.
  • the refresh rate of the control loop is at least twice as large as the maximum fluctuation frequency with which the optical disturbance changes through the boundary.
  • the inventive wavefront sensor-based arrangement allows the instantaneous, hardware-side correction of optical disturbances by an interface without a potentially time-consuming and time-consuming iteration method.
  • a further advantage of the wavefront sensor-based arrangement is that a clear result for the control of the wavefront modulator is achieved, whereas the application of iteration methods can potentially also lead to the determination of several solutions.
  • the wavefront sensor comprises a Hartmann-Shack type sensor, by means of which the phase information of the light reflected from the interface of the at least one illumination wavelength is converted into a measurable intensity distribution.
  • a Hartmann-Shack sensor generally consists of a microlens matrix and a spatially resolving detector. The position of the dot image produced by each microlens on the detector provides information about the local tilt of the wavefront. From the totality of all point images, the wavefront can be reconstructed and thus a possible distortion of the wavefront can be determined.
  • the wavefront sensor comprises an arrangement for carrying out holographic measurements.
  • the wavefront sensor detects the spatial intensity distribution of an interference pattern, which results from the coherent superposition of the light of the illumination wavelength reflected by the boundary surface with a reference wave.
  • the reference wave is generated by beam splitting of the light emitted by the illumination source.
  • the holography offers the possibility of fast and without to determine elaborate iterations, in particular the phase deformation of the reflected light from the interface.
  • the wavefront modulator of the inventive wavefront sensor-based arrangement comprises a combination of a plurality of adaptive optical correction elements.
  • image tilting by electrically operated galvanometer mirrors and defocus aberrations can be corrected by adaptive lenses.
  • Remaining optical disturbances can be corrected for example by a surface light modulator.
  • the individual adaptive optical correction elements are operated in series and in each case by a control circuit assigned to the respective correction element.
  • the wavefront modulator of the inventive wavefront sensor-based arrangement is based on a surface light modulator having a reflective illuminated surface.
  • the reflective area light modulator comprises a deformable mirror having a continuously illuminated surface or an array of micromirrors that are individually alignable.
  • the signal processing platform has an FPGA (Field Programmable Gate Array) or a graphics processor or a digital signal processor or a combination thereof.
  • FPGA Field Programmable Gate Array
  • the control rate of the drive of the wavefront modulator should be at least twice as high as the maximum occurring fluctuation frequency of the optical disturbance.
  • the illumination source emits at least two mutually different wavelengths for illuminating the flowing fluid
  • the wavefront sensor-based arrangement according to the invention has at least two illumination sources each emitting mutually different wavelengths for illuminating the flowing fluid. From these at least two wavelengths, a "synthetic wavelength" greater than each of the at least two wavelengths can be calculated, thereby increasing the unambiguity range of the wavefront inspection
  • the light reflected at the interface with at least two mutually different wavelengths is superimposed and analogous by means of the wavefront sensor the method known from the prior art as "absolute distance interferometry" determines the wavefront distortion due to the optical interference by the interface as an absolute phase deviation.
  • the orientation of the Wavefront modulator then takes place with regard to the measurement of the absolute phase deviation. This embodiment is particularly advantageous when considering unsteady disturbances, such as those caused by rough interfaces.
  • the flowing fluid contains tracers formed as fluorescent particles, either as tracers in the fluid, or the fluid intrinsically having fluorescent particles.
  • the method according to the invention comprises at least the following method steps: a. Illumination of a measuring field and thus of the flowing fluid through the interface with light of at least one illumination wavelength and interaction of the flowing fluid with the light of at least one illumination wavelength, wherein the light after reflection according to the Fresnel formulas at the interface having at least one illumination wavelength and after scattering at the fluorescent particles of the flowing fluid having a different wavelength from the at least one illumination wavelength;
  • the wavefront sensor-based method according to the invention can take place, for example, as follows: i. Illumination of the measuring field and thus of the flowing fluid through the interface with light of at least one illumination wavelength and interaction of the flowing fluid with the light of at least one illumination wavelength, the light after reflection at the interface having the at least one illumination wavelength and after scattering on the fluorescent particles of the flowing Fluids have a different wavelength from the at least one illumination wavelength;
  • ii ' Illumination of the measuring field and thus of the flowing fluid through the interface with the light of at least one illumination wavelength and interaction of the flowing fluid with the light of at least one illumination wavelength, wherein the light has the at least one illumination wavelength after reflection at the interface and after scattering on the fluorescent particles of the flowing fluid having a different wavelength from the at least one illumination wavelength; iii '. Separating the entirety of the light reflected from the interface and the light scattered by the fluorescent particles as a function of the wavelength into a portion having the at least one illumination wavelength and a portion having a different wavelength from the at least one illumination wavelength;
  • the described possible sequences of the wave front sensor-based method according to the invention can also be combined with one another such that both the light serving to illuminate the flowing fluid and the light reflected by the interface and the light scattered by the fluorescent particles interact with the controllable wavefront modulator.
  • the method according to the invention can also be used such that the measuring field is illuminated with at least two illumination wavelengths and, in analogy to the "absolute distance interferometry" method known from the prior art, the absolute phase deviation of the interference is determined by means of the wavefront sensor and used to align the wavefront modulator can.
  • wavefront sensor-based arrangement described in accordance with the invention naturally also apply in connection with the method according to the invention for wavefront sensor-based correction of optical interference and vice versa.
  • the invention is not limited to the illustrated and described embodiments, but also includes all the same in the context of the invention embodiments. Furthermore, the invention is not limited to the specifically described combinations of features, but may also be defined by any other combination of specific features of all individually disclosed individual features, unless the individual features are mutually exclusive, or a specific combination of individual features is not explicitly excluded.
  • FIG. 1 is a schematic representation of a wavefront sensorless device for correcting optical disturbances through an interface in an imaging flow measurement method
  • FIG. 2 shows a schematic representation of a further embodiment of a wavefront sensorless device for correcting optical disturbances through an interface in an imaging flow measuring method, wherein the flowing fluid contains particles
  • FIG. 3 shows a schematic representation of a wavefront sensor-based arrangement for correcting optical disturbances through an interface in an imaging flow measurement method.
  • a flow channel 2 flows through a fluid 21 in the flow direction 210, wherein the fluid 21 has an open boundary surface 21 1 toward the environment. Therefore, scattering at the open interface 21 1 causes a fluctuating optical disturbance.
  • the fluid contains 21 scattering particles (not shown).
  • a pattern 22 is arranged in a stationary manner.
  • the illumination source 3 emits the illumination light 31, which is directed via a beam splitter 4a and another beam splitter 4b to a surface light modulator 5 and reflected by it in the direction of the flow channel 2, so that the flowing fluid 21 and the pattern 22 through the interface 21 1 therethrough be illuminated.
  • the measuring field represents the illuminated region of the flow channel 2. Reflecting on the surface light modulator 5, a defined distortion (hereinafter represented in each case by an apostrophe in the designation of the light components) is impressed according to the orientation of the elements of the surface light modulator 5 of the wavefront of the light.
  • the entirety of the light 23 scattered by the scattering particles in the flowing fluid 21 and the pattern 22 is also reflected by the surface light modulator 5 and then by the beam splitter 4b in the direction of the camera 6 after transmission through the beam splitters 4a, 4b.
  • a wavelength bandpass filter 7 Disposed in front of the camera 6 is a wavelength bandpass filter 7, which only passes scattered light 23 'of a narrow wavelength range around the wavelength of the illumination light 31 to filter out unwanted background radiation which does not result from scattering at the flowing Fludi 21 or pattern 22.
  • the evaluation of the flow image and the pattern image and the control of the surface light modulator 5 is carried out with the signal processing platform 8, which is connected with the camera 6 and with the surface light modulator 5 information technology (indicated by dash-dot lines in Fig. 1).
  • the signal processing platform 8 can be a PC or an FPGA with the corresponding interfaces.
  • the flow image is first separated from the pattern image, for example by means of a linear search. Then, the pattern image deformed by scattering at the interface 21 1 is compared with the pattern 22 as an ideal target image, wherein a figure of merit, e.g. B. the deviation of the pattern image from the pattern 22, is calculated.
  • the quality factor is the normalized cross-correlation coefficient of the pattern image and the pattern, whereby the quality factor approaches the value 1 by decreasing deviation between the pattern image and the pattern, whereby the value 1 corresponds to the match of the pattern image and the pattern.
  • the signal processing platform 8 is connected to the area light modulator 5 in information technology and controls the orientation of the elements, the reflective surface thereof form, z. B. a plurality of individually controllable micromirrors.
  • the elements of the area light modulator 5 are driven by the signal processing platform 8 and its orientation iteratively varies with the aim that the quality factor increases by repeating the described method from the illumination of the flowing fluid 21 and the pattern 22 to the determination of the quality factor and orientation of the surface light modulator 5 ,
  • the iterative optimization is completed when the quality factor reaches a maximum or has exceeded a predetermined limit. Due to the fluctuating nature of the disturbance caused by the open interface 21 1, optimization proceeds essentially continuously.
  • the optimization process as well as the orientation of the area light modulator 5 must be carried out sufficiently fast.
  • the control rate of the arrangement 1 should be at least twice the maximum occurring fluctuation frequency of the disturbance.
  • the orientation of the surface light modulator 5 for optimizing the pattern image also results in the correction of the interference by the open boundary surface 211 with respect to the flow pattern.
  • the corrected flow pattern can be used with either the signal processing platform 8 or other signal processing platform to determine the flow parameters via known methods such as PIV, PTV, MTV.
  • FIG. 2 another embodiment of a wavefront sensorless Anoidnung 1 a for the correction of optical disturbances by a fluctuating interface 21 1 is shown in an imaging flow measurement method.
  • a fluid 21 flows through a flow channel 2 in the flow direction 210, wherein the fluid 21 has an open boundary surface 21 1 towards the environment. Therefore, scattering at the open interface 21 1 causes a fluctuating optical disturbance.
  • the fluid 21 contains fluorescent particles (not shown), while the pattern 22 fixedly arranged on the underside of the flow channel 2 is non-fluorescent.
  • the illumination source 3 emits the illumination light 31, which has an illumination wavelength ⁇ .
  • the illumination light 31 is directed via a beam splitter 4a and another beam splitter 4b to a surface light modulator 5 and reflected by it in the direction of the flow channel 2, so that the flowing fluid 21 and the pattern 22 through the interface 21 1 with illumination light 31 'of the illumination wavelength ⁇ be illuminated.
  • a defined distortion hereinafter represented in each case by an apostrophe in the designation of the light components
  • a portion of the illumination light 31 ' is scattered on the stationary pattern 22 and undergoes no wavelength change.
  • Another portion of the illumination light 31 ' is scattered by the fluorescent particles in the flowing fluid 21.
  • the scattered light 25 has the wavelength ⁇ 2, which i. d. R. different from ⁇ and according to the Stokes rule is greater than ⁇ .
  • a deflection of the light 231 'and the fluorescence light 25' scattered on the pattern 22 takes place by means of the beam splitter 4b in the direction of a dichroic filter 71.
  • the dichroic filter 71 has a reflection whose reflectance is a function of the wavelength of the light, so that the mirroring acts as a wavelength-selective beam splitter.
  • the dichroic filter 71 differs in a defined manner light of a certain wavelength or a wavelength range to a high degree and transmits light of another specific wavelength or another wavelength range to a high degree.
  • the dichroic filter 71 is designed such that the fluorescence light 25 'having the wavelength ⁇ 2 largely reflects through the dichroic filter 71 in the direction of a first camera 61 and thus the flow image is imaged on the camera 61.
  • the light 231 'with the wavelength ⁇ scattered on the pattern 22 is largely transmitted through the dichroic filter 71, and the pattern image is imaged on a second camera 62.
  • the evaluation of the flow image and the pattern image and the control of the surface light modulator 5 takes place with the signal processing platform 8, which is connected with the cameras 61, 62 and with the surface light modulator 5 information technology (indicated by dash-dot lines in Fig. 2).
  • the signal processing platform 8 can be a PC or an FPGA with the corresponding interfaces.
  • the deformed by scattering at the interface 21 1 pattern image is compared with the pattern 22 as an ideal target image, wherein a figure of merit, the z. B. the deviation of the pattern image from the pattern 22 is calculated.
  • the signal processing platform 8 is information technology connected to the area light modulator 5 and controls the orientation of the elements that form its reflective surface, based on an iterative optimization of the quality factor, as described for Fig. 1. By the alignment of the surface light modulator 5 to optimize the pattern image is also the correction of the interference by the open interface 21 1 with respect to the flow pattern.
  • the corrected flow pattern is evaluated with the signal processing platform 8 and can be used to determine the flow parameters via the known methods, such as PIV, PTV, MTV.
  • FIG. 3 shows an exemplary embodiment of a wavefront sensor-based arrangement 10 for correcting optical disturbances by a fluctuating interface 21 1 in an imaging flow measurement method.
  • a fluid 21 flows through a flow channel 2 in the flow direction 210, wherein the fluid 21 has an open boundary surface 21 1 to the environment, and whereby a fluctuating optical disturbance is caused by scattering at the interface 21 1.
  • the fluid 21 contains fluorescent particles (not shown).
  • the illumination source 3 emits the illumination light 31, which has an illumination wavelength ⁇ .
  • the illumination light 31 Via a reflection prism 9a or a mirror and a beam splitter 4a, the illumination light 31 is directed to another beam splitter 4b and reflected by this onto the surface light modulator 5, whereby the wavefront of the illumination light 31 a defined distortion (represented by an apostrophe in the designation of the light components) is imprinted.
  • the wavefront of the illumination light 31 a defined distortion represented by an apostrophe in the designation of the light components
  • Fresnel light 24 A portion of the illumination light 31 'is reflected at the interface 21 1 according to Fresnel's formulas due to the refractive index difference between the fluid 21 and the environment, and experiences no wavelength change.
  • the light reflected at the interface with ⁇ is hereinafter referred to as Fresnel light 24.
  • Another portion of the illumination light 31 ' is scattered by the fluorescent particles in the flowing fluid 21.
  • the scattered light 25 has the wavelength ⁇ 2, which is generally different from ⁇ and according to the Stokes rule is greater than ⁇ .
  • the Fresnel light 24 and the scattered light referred to below as fluorescence light 25 are deflected by the reflection prism 9b in the direction of the surface light modulator 5 and reflected by this after transmission through the beam splitter 4b.
  • the Fresnel light 24 'and the fluorescence light 25' are deflected by means of the beam splitters 4b and 4a in the direction of a dichroic filter 71.
  • the dichroic filter 71 has a reflection whose reflectance is a function of the wavelength of the light, so that the mirroring acts as a wavelength-selective beam splitter. Therefore, the dichroic filter 71 differs in a defined manner light of a certain wavelength or a wavelength range to a high degree and transmits light of another specific wavelength or another wavelength range to a high degree.
  • the dichroic filter 71 is formed so that the fluorescent light 25 'with the wavelength ⁇ 2 largely transmitted through the dichroic filter 71 in the direction of the camera 6 and the flow image is imaged on the camera 6.
  • the Fresnel light 24 'with the wavelength ⁇ is largely reflected at the dichroic filter 71, and then deflected by means of a further reflection prism 9c in the direction of a wavefront sensor 10.
  • the wavefront sensor 10 may, for. B. be designed as a Hartmann-Shack sensor.
  • the detected by the wavefront sensor 10, caused by the interface 21 1 distortion of the wavefronts of the Fresnel light 24 ' is evaluated with the signal processing platform 8.
  • a parameter set for the adjustment of the area light modulator 5 is then calculated in order to correct the detected wavefront distortion by aligning the elements of the area light modulator 5.
  • the control of the elements of the surface light modulator 5 is also carried out by the signal processing platform 8.
  • the signal processing platform 8 with the wavefront sensor 10 and the surface light modulator 5 information technology connected (indicated by dash-dot lines in Fig. 2).
  • the signal processing platform 8 can be a PC or an FPGA with the corresponding interfaces.
  • the signal processing platform 8 is additionally connected to the camera 6 in terms of information technology.
  • the arrangement 1 comprises a closed loop.
  • the update rate of the control loop is at least twice as large as the maximum occurring fluctuation frequency of the optical disturbance through the open interface 21 1.
  • the correction of the disturbance by the open boundary surface 21 1 with respect to the flow image is likewise carried out.
  • the corrected flow pattern can then for Determining the flow parameters over the known methods, such as PIV, PTV, MTV, are used.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Electromagnetism (AREA)
  • Fluid Mechanics (AREA)
  • Investigating Or Analysing Materials By Optical Means (AREA)

Abstract

Une interface, variant généralement dans le temps, entre une pluralité de fluides en écoulement ayant des indices de réfraction différents, par exemple l'interface entre l'eau et l'air avec la surface de l'eau libre, représente une perturbation optique. Les procédés de mesure d'écoulement optique qui sont effectués par le biais de l'interface sont affectés par cette perturbation, ce qui peut entraîner des écarts de mesure importants, voire empêcher totalement une mesure. L'invention contribue à résoudre ce problème métrologique en proposant des dispositifs (1, 1a, 1') et des procédés de correction instantanée et matérielle de perturbations optiques provoquées par une interface fluctuante (211). Pour cela, on introduit dans le trajet de faisceau du procédé de mesure optique un modulateur de front d'onde (5) qui compense activement, au moyen d'une régulation, la perturbation optique générée. L'invention permet de réaliser des mesures d'écoulement optiques par le biais d'une interface fluctuante. Elle ne se limite pas à une technique de mesure d'écoulement unique, mais peut être mis en œuvre dans tous les procédés d'imagerie connus. L'invention peut être utilisée dans un grand nombre d'applications techniques. On peut mentionner à titre d'exemples : les interfaces liquide-air, par exemple dans les canaux d'eau à surface ouverte ; les écoulements pelliculaires, par exemple en génie chimique pour le refroidissement, la purification ou la distillation ; les jets de liquides dont les surfaces fluctuent de toutes parts ; les mesures en gouttes lévitantes ou adhérentes sur une base opaque, ou les bulles de gaz dans les liquides. L'invention est également appropriée pour la correction de perturbations causées par des gradients de température lors de combustions, de gradients de pression, par exemple dans des coups de bélier, ou de gradients de concentration, par exemple dans des procédés d'électrolyse.
PCT/EP2018/068669 2017-07-11 2018-07-10 Dispositif et procédé de correction de perturbations pour procédés de mesure d'écoulement optiques WO2019011916A1 (fr)

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EP18743430.3A EP3652578B1 (fr) 2017-07-11 2018-07-10 Dispositif et procédé de correction de perturbations pour procédés de mesure d'écoulement optiques
CN201880046397.4A CN110914736B (zh) 2017-07-11 2018-07-10 用于对成像流动测量方法进行干扰校正的布置和方法
US16/628,391 US10921585B2 (en) 2017-07-11 2018-07-10 Arrangement and method for disturbance correction for imaging flow measuring processes

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KR20230042106A (ko) * 2020-07-29 2023-03-27 어플라이드 머티어리얼스, 인코포레이티드 마스크리스 리소그래피 시스템들을 위한 프로세스, 시스템, 및 소프트웨어
CN112881386B (zh) * 2021-01-11 2022-04-05 西安交通大学 一种六自由度运动条件下窄缝通道可视化实验装置及方法
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CN114838900A (zh) * 2022-05-09 2022-08-02 中山大学 一种用于风洞实验的光学补偿方法及装置
CN114964716B (zh) * 2022-08-01 2022-10-04 北京航空航天大学 一种圆柱液体射流表面微小扰动的测量装置及方法
CN116580076B (zh) * 2023-07-10 2023-09-12 中国空气动力研究与发展中心计算空气动力研究所 获取包含模型边界的粒子图的设备、方法、装置及介质

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7118216B2 (en) 2001-08-30 2006-10-10 University Of Rochester Method and apparatus for using adaptive optics in a scanning laser ophthalmoscope
DE60223130T2 (de) 2001-09-28 2008-08-07 Raytheon Co., El Segundo Kontrolle von hochleistungs-strahlen mit wellenfront-korrektur unter benutzung von phasenkonjugation und adaptiver optik
US20100195048A1 (en) 2009-01-15 2010-08-05 Physical Sciences, Inc. Adaptive Optics Line Scanning Ophthalmoscope
WO2012100763A1 (fr) * 2011-01-24 2012-08-02 Technische Universität Dresden Procédé de détermination de vitesses dans des écoulements et capteur de champ phase-fréquence-vitesse
WO2014122156A1 (fr) * 2013-02-06 2014-08-14 Rheinmetall Waffe Munition Gmbh Procédé et dispositif destinés à recevoir et traiter les signaux optiques en provenance d'un objet volumineux
US20150160118A1 (en) 2013-12-06 2015-06-11 BacterioScan Inc. Method And System For Optical Measurements Of Contained Liquids Having A Free Surface

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN204461710U (zh) * 2014-12-30 2015-07-08 黄真理 一种激光诱导荧光三维流体探测系统

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7118216B2 (en) 2001-08-30 2006-10-10 University Of Rochester Method and apparatus for using adaptive optics in a scanning laser ophthalmoscope
DE60223130T2 (de) 2001-09-28 2008-08-07 Raytheon Co., El Segundo Kontrolle von hochleistungs-strahlen mit wellenfront-korrektur unter benutzung von phasenkonjugation und adaptiver optik
US20100195048A1 (en) 2009-01-15 2010-08-05 Physical Sciences, Inc. Adaptive Optics Line Scanning Ophthalmoscope
WO2012100763A1 (fr) * 2011-01-24 2012-08-02 Technische Universität Dresden Procédé de détermination de vitesses dans des écoulements et capteur de champ phase-fréquence-vitesse
WO2014122156A1 (fr) * 2013-02-06 2014-08-14 Rheinmetall Waffe Munition Gmbh Procédé et dispositif destinés à recevoir et traiter les signaux optiques en provenance d'un objet volumineux
US20150160118A1 (en) 2013-12-06 2015-06-11 BacterioScan Inc. Method And System For Optical Measurements Of Contained Liquids Having A Free Surface

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
CUI, M.; YANG, C.: "Implementation of a digital optical phase conjugation system and its application to study the robustness of turbidity suppression by phase conjugation", OPTICS EXPRESS, vol. 18, no. 4, 2010, pages 3444, XP055026360, DOI: doi:10.1364/OE.18.003444
CZARSKE, J. W.; KOUKOURAKIS, N.; FREGIN, B.; KÖNIG, J.; BÜTTNER, L.: "Adaptive flow-field measurements using digital holography", PROCEEDINGS OF SPIE, vol. 10074, 2017, pages 10074F - 1,100740F-7
RICHARD, H.; RAFFEL, M.: "Principle and applications of the background oriented schlieren (BOS) method", MEASUREMENT SCIENCE AND TECHNOLOGY, vol. 12, 2001, pages 1576 - 1585, XP001208969, DOI: doi:10.1088/0957-0233/12/9/325

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DE102017211837A1 (de) 2019-01-17
US20200218064A1 (en) 2020-07-09
US10921585B2 (en) 2021-02-16

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